Dosing guns used for example for filling of joints or packing gaps with liquid adhesives or silicone pastes.
Dosing guns for liquids and pastes of the above-mentioned type are already known. Such a gun consists of a housing on which is provided a trigger device with a trigger lever, which through repeated operations of the trigger lever and an associated driving mechanism, moves a piston rod with a piston in an axial direction. It is in this manner, for example, possible to empty a liquid or paste filled cartridge which has been inserted into the dosing gun through a discharge nozzle.
A disadvantage in dosing guns of this design is that through the jerky operation of the piston rod, liquid or paste is moved very unevenly out of the cartridge and thus a satisfactory operation is hindered.
Therefore, the basic purpose of the invention is to provide a dosing gun of the above-mentioned type, with which the piston rod of the dosing gun is movable evenly in axial conveying direction, so that liquid or paste can be conveyed evenly and continuously out of the cartridge and thus a satisfactory operation is made possible.
The advantages achieved with the invention consist in particular in the piston of the piston rod being evenly movable in axial conveying direction and liquid or paste thus being able to be moved evenly and continuously out of the cartridge. This is achieved, by the inventive dosing gun, substantially through a spring, preferably a gas-pressure spring arranged around the piston rod, receiving an initial tension with the help of a trigger lever of a trigger device. The initial tension can be controlled by a band brake such that a cord secured to the piston rod can be wound onto a cord drum equipped with a brake drum onto which acts a brake band connected to a rocker arm when the trigger lever operates or releases a spring mechanism of the rocker arm and a pressure rod secured thereon with a roller acts onto the cord.